1. Field of the Invention
The present invention relates to a display panel and a display device. More particularly, the present invention relates to an organic light emitting panel including a spacer and a display device including the same.
2. Description of the Related Art
A display device such as a liquid crystal display (LCD), an organic light emitting diode (OLED) display, and an electrophoretic display includes a field generating electrode and an electro-optical active layer. For example, the organic light emitting diode (OLED) display device includes an organic light emitting layer as the electro-optical active layer. The field generating electrode is connected to a switching element such as a thin film transistor to receive a data signal, and the electro-optical active layer converts the data signal into an optical signal to display an image.
Among the display devices, since the organic light emitting diode (OLED) display as a self-light emitting type display device that does not require a separate light source, it is advantageous in terms of power consumption, response speed, viewing angle, and contrast ratio.
The organic light emitting diode (OLED) display includes a plurality of pixels such as red pixels, blue pixels, green pixels, and white pixels, and may express full colors by combining the pixels. Each pixel includes an organic light emitting element, and a plurality of thin film transistors for driving the organic light emitting element.
The light emitting element of the organic light emitting diode (OLED) display includes a pixel electrode, an opposed electrode, and a light emitting layer arranged between the two electrodes. One of the pixel electrode and the opposed electrode becomes an anode, and the other electrode becomes a cathode. An electron injected from the cathode and a hole injected from the anode are coupled with each other in the light emitting layer to form an exciton, and the exciton emits light while discharging energy. The opposed electrode is formed throughout a plurality of pixels to transfer a predetermined common voltage.
In general, an insulating layer is arranged on a plurality of thin film transistors, and a conductive layer including the pixel electrode or other signal electrode is arranged on the insulating layer. The insulating layer includes a via hole, and the conductive layer on the insulating layer and the conductive layer such as the electrode of the thin film transistor under the insulating layer may be electrically connected to each other through the via hole of the insulating layer.
To improve a characteristic of the display panel, when forming the thick insulating layer on the thin film transistor, a step of the via hole of the insulating layer may be high. Since the via hole has a concave shape having the high step, if another layer is arranged on the via hole, the concave shape of the via hole is transferred to that layer such that diffused reflection of external light may be generated at the concave portion. This may be recognized as a stain on the outside. Particularly, when the thickness of the layer arranged on the via hole is thick, the step of the transferred concave shape is increased such that the display defect due to the stain may be serious.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not constitute prior art as per 35 U.S.C. 102.